1. Field of the Invention
The present invention relates to a gradient magnetic coil having resin material infiltrated thereto, a method of manufacturing the gradient magnetic coil, and a magnetic resonance imaging (MRI) apparatus having the gradient magnetic coil.
2. Description of the Related Art
A medical MRI apparatus generally includes a gantry. The gantry generally includes magnetostatic magnets, gradient magnetic coils, cooling pipes, and the like.
The gradient magnetic coils include a plurality of coils and generate gradient magnetic field when electric current flows through the plurality of coils. The coils are formed of conductive line members wound in a winding pattern corresponding to a gradient magnetic field pattern to be generated. Resin materials are filled into gaps between identical line members or gaps between line members of different coils. The resin materials serve to provide insulation between the line members and maintain the winding state of the line members which are would in the above-mentioned winding pattern.
However, recent MRI apparatuses require greater gradient magnetic field and fast initial start-up. For this reason, it is necessary to supply a large amount of current to the gradient magnetic coils. Accompanied by the large current supply, the coils are more likely to emit an increased amount of heat. Thus, cooling of the gradient magnetic coil is becoming important (see, U.S. Pat. No. 6,741,152, for example).
As the resin material, an epoxy resin has been used so far. Since the epoxy resin has low viscosity at high temperature, it can be suitably used in spreading it into all the corners of the coil gaps, but it has extremely low heat conductivity. Accordingly, in a gradient magnetic coil in which the epoxy resin is filled into the gaps of the coils, the epoxy resin acts as a barrier preventing the heat generated in the coil from being dissipated toward the cooling pipes, thereby lowering the cooling performance.
In view of those circumstances, it is required to improve heat dissipation efficiency of the gradient magnetic coil.